MY BIO
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I am a PhD candidate in Earth Sciences at the University of Southern California, interested in the coevolution of the macroscopic biosphere and the physical planet, which I look at through the lens of sedimentology, geophysical field techniques, petrography, stable isotope geochemistry, cosmogenic nuclide geochemistry.
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I am most interested in how large organisms (e.g., plants, large mammals, etc) change geomorphology, biogeochemical cycles, and climate.
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I am investigating how humans have affected erosional fluxes (i.e., soil depletion) in the Channel Islands of California, starting from the first humans on the island (Ancestral Chumash ~13,500 BP) to the arrival of ranchers and herders on the island (~1800 AD) to the present.
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I am studying whether the evolution of trees in the Late Paleozoic Era (~450-300 Ma) altered the sensitivity of terrestrial silicate weathering and potentially caused a drawdown in atmospheric carbon dioxide.
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I am examining how the devastating 2025 Los Angeles Fires has changed geomorphology and hydrogeology.
EDUCATION
I majored in Computer Engineering as an undergraduate and worked for a few years in the Bay Area (California) as a Software Engineer. I did not find that subject intellectually stimulating enough to hang on to throughout my life. Science has always fascinated me. After graduation I had the opportunity to travel across the US, multiple times. This reignited my love for the natural sciences that had probably developed in my childhood. My parents are soil scientists, and I would accompany them on field trips as well as extensive Himalayan treks; this would stimulate my curiosity, and fill me with fascination about the natural world.
After much thought, I decided to make a giant leap of career switchover to pursue graduate school in Geology. I started off by taking online courses while working full time. I then quit my job to take a field course at OSU; after which, I boarded the Amtrak to travel the country and meet potential advisers. I started my master's program in Geological Sciences at California State University, Northridge (CSUN) in August 2019 with Dr. Jen Cotton. I started my PhD at the University of Southern California (USC) during the Fall of 2021 with Dr. Frank Corsetti and Dr. Josh West as my advisers.
August 2021 - Present
PH.D. IN EARTH SCIENCES, UNIVERSITY OF SOUTHERN CALIFORNIA.
ADVISER: DR. JOSH WEST & DR. FRANK CORSETTI
August 2019 - May 2021
January 2018 - December 2018
NON DEGREE STUDENT
OREGON STATE UNIVERSITY
CORVALLIS, OR
August 2012 - May 2017
BS IN COMPUTER ENGINEERING
PURDUE UNIVERSITY
WEST LAFAYETTE, IN
RESEARCH INTERESTS
I am most interested in the Earth System. Particularly, the interaction and interrelation of the macroscopic biosphere and the physical planet (morphology, climate, lithosphere, cryosphere) fascinate me.
I do not see the natural world through the lens of subjects and methods, and I strive to keep my research interests broad.
TERRESTRIAL ECOSYSTEM EVOLUTION
Terrestrial primary productivity is dominated by plants. Significant events during the evolution of plants such as the Devonian spread of trees, the Cretaceous spread of flowering plants, and the Cenozoic spread of grasses shaped the global landscape. Forests altered river dynamics and sedimentation patterns, they restructured the biogeochemical cycling of elements such as Carbon (thereby determining atmospheric carbon dioxide), Silica, Lithium, Sulpher, Phosphorous, and Nitrogen, and enabled the colonization of land by animals and affected oceanic biota (by making nutrients and chemicals available to marine organisms to utilize).
COEVOLUTION OF MEGAFAUNA AND EARTH
Megafauna (Humans, Elephants, etc) play an outsized role in impacting the various facets of the earth system whether it be through changing erosion rates (Cummings & Cummings, 2003, Kemp, 2020) or nutrient cycling (Doughty et al., 2013).
However, these models have yet to be tested and my hope is to better understand the role of megafauna on the Earth System though the lens of field research and geochemistry.
EARTH-LIFE INTERACTIONS
A fundamental connection between the biotic system and the physical planet through various climate and weathering feedbacks has been hypothesized to have kept the Earth habitable over geologic time. Evaluating this hypothesis during important events during the biotic evolution of flora and fauna allows me to gain a deeper philosophical understanding of our planet.
METHODS
SEDIMENTOLOGY & BASIN ANALYSIS
Carbonate Reefs (hunting for Paleozoic sponge spicules and brachiopods), Fluvial and Lacustrine environments (Mesozoic and Cenozoic fluvial deposits)
ISOTOPE GEOCHEMISTRY + BIOMARKER ANALYSIS
Stable isotopic analysis: Lithium and Carbon Isotopes
Cosmogenic nuclids: Beryllium-10 and Carbon-14 in-situ quartz
Analysis of Polycyclic Aromatic Hydrocarbon (PAH) and long chain n-alkanes
CARBONATE PETROGRAPHY
Optical and Cathodoluminescent microscopy
Geophysical Field Methods
Electrical resistivity tomography (ERT)
Peer-Reviewed Publications
Violette, M. J., Hyland, E., Burgener, L., Ghosh, A., Montoya, B. M., & Kleiner, M. (2024). Meta-omics reveals role of photosynthesis in microbially induced carbonate precipitation at a CO2-rich geyser. ISME Communications, 4(1), ycae139-. https://doi.org/10.1093/ismeco/ycae139
Ghosh A., Cotton, J., Hauswirth, S., Hyland, E., Azmi, I., Tineo, D., Raigemborn, M.S., Hayduk, T., Insel, N. Precipitation controlled vegetation and fire regimes during the Late Miocene-Pliocene in South America. (in-prep)
Rafter, M., Cotton, J., Hyland, E., Ghosh, A., Raigemborn, M., Tineo, D. and Insel, N. New Paleoclimate proxy for growing season precipitation using paleosol geochemistry. (in-prep)
Azmi, I., Hyland, E., Cotton, J., Ghosh, A., Raigemborn, M.S., Tineo, D., Insel, N. Late Miocene expansion of grasslands in NW Argenitna linked to shifting hydroclimate. (in-prep)
Ghosh, A., & Varadachari, C. (2015). Theoretical Derivations of a Direct Band Gap Semiconductor of SiC Doped with Ge. Journal of Electronic Materials, 44(1), 167–176. https://doi.org/10.1007/s11664-014-3424-7
Awards/Grants
Total grant funding of $32,477 over four years (all small grants, I am an international student and cannot apply for large research fellowships). These grants have covered the cost of most of my fieldwork and a substantial part of the labwork.
2025- M. Gordon "Reds" Wolman Graduate student research award, $1000
2024- Geologic Society of America, Geobiology & Geomicrobiology best poster award
2024- GSA/NSF AGeS-III Geochronology Grant, $10,000.
2023- Exploration Fund Grant, $5000
2023- Lewis & Clark Fund for Exploration and Field Research, $5000
2023- 2023 Lewis and Clark Field Scholar
2022- Geological Society of America Graduate Student Grant, $2277
2022- Evolving Earth Foundation Student Grant, $3000
2022- Society of Sedimentary Geology Student Grant, $1000
2021- Gene and Sue Fritsche GeoTrek Award for Field Geology, $1000
2020- Hanna Summer Research Scholarship, $3000
2019- CSUN Thesis Support Grant, $1200
CONTACT
Zumberge Hall of Science (ZHS), University of Southern California
aditghos (dot) 605 (at) usc (dot) edu
